Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnlyHint=true, destructiveHint=false, and openWorldHint=true, so safety is covered. The description adds real value beyond them by disclosing which fields are deliberately omitted (street addresses, home phone, notes) and the underlying GET /contacts endpoint, though it says nothing about auth or rate limits.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Three short sentences: result contents first, then filters, then exclusions, then the endpoint. Every clause carries information and nothing is padded.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

For an 8-param read tool with no output schema, the description usefully compensates by enumerating returned fields and calling out omitted ones, and pagination semantics live in the schema. It stops short of describing result ordering guarantees or the shape of the paginated reply, but the essentials are present.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

With 88% schema description coverage, the schema already documents pagination (top/skip/next_skip), sorting, and date bounds. The description restates the filterable fields (status, id, creation date) without adding format or behavioral detail beyond the schema, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb and resource ('List contacts') and enumerates the returned fields (name, email, phones, city, status, creation date), which cleanly separates it from sibling list_* tools for clients, invoices, projects, etc. An agent can identify the resource and result shape without opening the schema.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It names the filterable dimensions (status, id, creation date), which implies how to narrow results, but gives no explicit when-to-use guidance, no pointer to a sibling tool, and no exclusions. Usage is inferable but not prescribed.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.